The aforementioned U.S. patent contains a disclosure of an aiming device for a gun wherein the user keeps both eyes open. The device which is mounted on the gun projects a spot source of light rearwardly toward one eye of the user with the result that the user in viewing the target with the other eye sees the spot of light superimposed thereon. So long as the device is correctly aligned on the gun, the user has only to point the gun until the light spot is superimposed on the target in order to correctly aim the gun. This is obviously an easier operation than a conventional rear and front sight arrangement in which the two sights have to first be aligned with the shooter's vision and the two then positioned in alignment with, or immediately below, the desired target. The present invention represents an improvement on the light source which is employed in the aiming device of the aforementioned patent. It is contemplated that the aiming device of the present invention will have utility not only with firearms but also for optical instruments such as telescopes, levels, sextants, and the like as well as parabolic microphones or any other apparatus which must be manually aimed by the user.